Tire pump



`Ian. 12, 1937. w K THORNTON 2,067,358

TIRE PUMPl Filed Sept. 8, 1934 ATTORNEYJ'N Patented Jan, l2, 1937 Unirse stares PATENT OFFICE TIRE PUMP WilliamKenneth Thornton, Woodbridge, N. J.

Application September 8, 1934, Serial No. 743,236

Claims.

This invention relates to improvements in pumps for pneumatic tires and the like.

It is a feature of this invention to provide an improved pump for automobile tires which 5 may be termed continuously acting, which is so congured and arranged as to be adapted to be included as part of the hub or hub cap of an automobile wheel.

A further feature of this invention is the provision of an improved tire pump which is adapted to automatically maintain a desired pressure in a tire.

Another feature of this invention is the provision of an improved tire pump adapted tov be mounted on the axis of rotation of an automobile wheel and which includes substantially only a single moving part.

These and other desirable features and advantages oi the present invention will be described in the accompanying speciication and illustrated ini the drawing, certain preferred structural embodiments being shown by way ci illustration only, for, since the underlying principles may be incorporated in other specific mechanical devices, it is not intended to be limited to the ones here shown, except as such limitations are clearly imposed by the appended claims.

In the drawing like numerals refer to simi* lar parts throughout the several views, of which Fig. 1 is an elevation of the hub of an automobile wheel showing a tire pump as an associated part of a wheel hub cap and showing connection to the tire valve;

v Fig. 2 is a vertical section of the pump construction shown in Fig. 1 and taken on line 2-2 of Fig. 1

Fig. 3 is a view similar to Fig. 2 showing vertical sections through a modified form of tire pump; and

Fig. 4 is a cross-section taken on line i--li of Fig. 3.

Referring now more specically to the drawing, the pump I6 is shownattached to a hub plate 2i) of an automobile wheel as by means of a threaded collar Ilia. The pump is connected to an automobile tire 30 through a exible conduit or tubing 3I, the tire being provided with a special T-valve 32, permitting the tire to be blown up in the usual manner.

The tire pump comprises a bottom member I I and a top I2 secured together by means of bolts and nuts I3, a diaphragm or pump actuating and driving member I4 being interposed ,55 therebetween and serving also as a gasket. The

Vinterior continuous opening (Cl. ZBO-35) member II may be screwed on the hub of a Wheel or fastened thereto in any desired manner.

In the form shown more in detail in Fig. 2 a chamber Ila is formed in the bottom cup be- 5 tween the diaphragm Ill and the base of the casing. A suitable nipple or connection 33 is tapped into this chamber IIa and the conduit or channel 3d formed thereby is of suiiicient size to permit the unrestricted flow of air in 10 and out of chamber I Ia.

The diaphragm I4 of rubber, leather or other suitable material for use in diaphragm pumps, is secured to the base I6 of a piston I5 by means of clamping plates Il. These plates are 15 adapted to screw up on the threaded base I6 of the piston I5. The piston I5 coacts with a pump cylinder I9 and is provided with an I8, opening into the pump cylinder or casing I9. The piston 20 may be provided with a detachable head 2I comprising a centrally apertured body portion having a shoulder 22 and threaded portion 23 adapted to screw into a threaded socket in the end of the member I5. A nexible washer 24 25 of leather or other suitable material is disposed between the head 2l and the body of the piston I5 and is held in position by screwing up the head 2i into the socket formed in member I5. The one-way valve formed in the 30 head ZI of the piston, includes a ball 25 urged by a spring 26, the spring being adapted to seat against internal seat formed in member I5.

The pump cylinder or casing E9 is provided with ports 2l, normally in free communication 35 with chamber 4E), formed by the casing member I2. A screw 4I is tapped into the head or boss of the cover I2 and is adapted to be removed to permit access to the valved head 2| of the piston I 5. The pump chamber I9 may be cast 40 integrally with the cover I2, or may be secured thereto by welding, as indicated at"42.

A compression spring d3 of suitable size is tted over the pump chamber I9 and urges the diaphragm I4 inwardly toward the wheel. The 45 chamber 4U in cover I2 may be provided with ports lill giving access to the air. These apertures may be screened, as indicated generally at Illa to prevent the introduction of dirt and the like into the system. 50

In operation the tire may be pumped up to the desired air pressure through T-valve 32. In this operation, the chamber IIa is lled with air at the same pressure as the tire, the tire casing and the chamber lia being in free com- 56 munication, as above indicated. The air in the chamber lla isretained in place by the one-Way valve in the pump piston. The pressure of the air in the tire acts on diaphragm ifi and forces the latter outwardly against the calibrated pressure of spring lli-3. In such position the head 2l of the piston E5 is aboutJ flush with the ports 2l in the pump chamber i9, permitting free access of air to the chamber lil.

If the tire t@ commences to deflate through any cause, it is subjected to a considerable amount of flexing in passing over the road, and more particularly when contacting with bumps such as caused by depressions in the road or rocks. When the partially deflated tire is thus flexed, a considerable pressure is built up tempo-rarily in the tire and this pressure is transmitted through chamber lla to the diaphragm ifi. As these pressures are in the nature of impacts, the diaphragm i4 is carried or pushed out of position carrying the plunger l5 of the pump mechanism into the pump chamber E55. rIn this movement of the piston l5 into the chamber it, the head 2l of the piston passes and closes the ports 2l of the pump chamber. Continuance of the movement of piston l5 causes the entrapped air in chamber l@ to be further compressed so that it overcomes the back pressure exerted by the air in chamber l la and the pressure of spring 25 normally maintaining ball Valve 25 seated in closed position. Thus the compressed air in chamber i9 is forced back into chamber llc. As the number of impacts to which a partly deflated tire is subjected are quite numerous, the increments of air pumped into the tire casing by the piston l5 are considerable in number.

In running an automobile under ordinary` road conditions, it is` found possible to maintain and restore an air pressure within a run of one or two miles. When the air in the casing 310 has been restored to its normal pressure, the diaphragm lll will be maintained in the desired state of equilibrium by the opposing forces of the air in the tire and the compression spring 433.

Referring now more particularly to Figs. 3 and 4, a modiiied form of construction is shown in which the hub cap 5B is provided with a pump casing or cylinder 5l, secured thereto in any desired manner, and preferably by tapping same into the head 52 of the cover. A screw plate 53 also engages the head 52 and serves to seal off the pump chamber from the outside air. The casing El of the pump chamber is provided with continuous walls and is not apertured as in the form shown in Fig. 2. The piston l5 of the pump is provided with a modified piston heard 55 having longitudinal peripheral slo-ts 5t formed therein. The usual washer 2d is provided for the piston assembly, the piston also being provided With the usual ball valve E5 and spring 25. The bottom of the pump casing 5l is internally belled or flared, as indicated at 51, to permit the smooth passage of the piston ring 2d into contact with the walls of the pump chamber.

In normal unexed operation, the piston head 55 extends a suflicient distance into the pump chamber to seat itself properly therein, permitting free access of air from the chamber 4B to the interior of the pump cylinder through the longitudinal slots or ports 56. When the piston is moved inwardly of the pump chamber, the piston ring or washer 2li is moved past the bell mouth into engagement with the walls of the pump chamber, thereby sealing the latter o from the atmosphere and permitting the contained air therein to be compressed by further movement of the pump piston.

It will now be appreciated that there has been provided novel pump mechanisms, particularly adapted for use in automobile wheels and intended principally for mounting on the axes of said Wheels, whereby any eects due to centrifugal action on rotating members is done away with. In addition, the novel pump mechanism of the present invention is formed with substantially a single moving part, thus avoiding difficulties normally incident to the association of a number of moving parts in any pump mechanism. Further features of novelty of the present invention reside in the use of an auxiliary air pressure chamber to augment the action of a compression spring for maintaining a desired air pressure balance in the tire and pump system. Another feature of advantage herein disclosed resides in the incorporation of a novel pump mechanism in a hub cap for automobile Wheels, whereby the latter may be mounted in place of or form a part of the usual hub cap and permits direct connection to the tires, whereby to maintain them at a desired operative pressure under all circumstances, avoiding the troubles consequent upon the usual slow leakage encountered in use.

While the foregoing description has been set forth in general and in detail in respect to speciiic ideas, it will be understood that changes and modifications may be made therein and that such changes and modiiications are to be considered Within the scope of the invention as defined in the subjoined claims.

What is claimed is:

l. A pump, comprising, incombination, a pair of body portions and a flexible diaphragm secured therebetween, one of said body portions forming a chamber with the diaphragm, a Huid reservoir chamber, said fluid reservoir normally being subjected to varying operating pressures, the other of said body portions forming a second chamber with the diaphragm and being provided with a pump cylinder casing having apertures opening into the said second chamber and the latterk being in turn in communication with the eX- ternal air; a hollow piston mounted in the pump cylinder and secured to the flexible diaphragm for actuation thereby, the said hollow piston being provided with a one-way valve structure effecting communication between the pump cylinder and the first said chamber.

2. An automatic pump assembly, comprising,

in direct communication with said in combination, a fluid reservoir, a two-part casin communication with the chamber in which it is disposed and the said piston being provided with a one-Way valve and secured to the said diaphragm whereby to be actuated thereby and to provide uni-directional access of fluid from the said pump cylinder to the said uid reser- Voir.

3. An air pump comprising a diaphragmactuated pump mechanism, a casing for the mechanism comprising a cover Vand a bottom portion having an outlet, a iluid reservoir connected to the outlet, the said casing being divided into two parts by the diaphragm and forming two chambers therewith, the chamber formed by the cover and the diaphragm being in free communication with the air; an apertured and valved piston mounted on the diaphragm and adapted to move therewith, a pump cylinder mounted on the cover of the device and adapted to receive the valved piston in operative engagement; ports in the pump cylinder permitting access of air from the chamber formed by the casing cover and the diaphragm, the said ports being adapted to be closed by the piston upon movement thereof by the diaphragm.

4. A pump mechanism comprising a two-part casing having an apertured cover and a fluidtight bottom portion, the bottom portion being provided with an outlet, a pump cylinder and associated piston in the casing, a diaphragm in the casing and dividing the same into two chambers, a uid reservoir connected to the said outlet, one of the said chambers communicating with said reservoir, the chamber formed by the cover and the diaphragm serving as a housing for the pump cylinder; a compression spring surrounding the said pump cylinder and bearing against the diaphragm, the piston being hollow and being secured to the diaphragm and adapted for sliding engagement in the pump cylinder, the

said piston being provided with a one-way valve, and ports in the pump cylinder normally open to the chamber formed by the diaphragm and cover and adapted to be closed by the piston upon movement of the pump diaphragm.

5. A pump mechanism, including, in combination, a pair of opposed body portions comprising an apertured cover and a bottom provided with an outlet, the said pump having a exible diaphragm between the cover and the bottom and dividing the same into two chambers, a fluid reservoir, the bottom of the pump mechanism forming a chamber with the diaphragm, the so-formed chamber being in direct communication with the iiuid reservoir, the said cover being provided withr` a pump cylinder in the chamber formed With the said diaphragm, said pump cylinder having a belled mouth opening into the said second chamber and being secured to the cover, a screw plate secured to the said cover and serving as a closure for the pump cylinder, a hollow piston in the pump cylinder and mountedV on the exible diaphragm, the piston head being provided with a series of peripheral slots adapted to permit the access of air from the second said casing chamber to the pump cylinder, the said slots being so constituted and arranged as to be closed by the walls of the cylinder when the piston is urged into the body of the pump cylinder by the movement of the diaphragm.

WILLIAM KENNETH THORNTON. 

